Abstract

An improved ignition system is provided for an internal combustion engine having a combustion chamber and a conventional carburetor system, a conventional fuel injection system or a conventional gas mixing system, for feeding an ambient combustible fuel-air mixture to the combustion chamber. In this system, a high speed injector is fed with a gaseous fuel between a spark gap provided by a spark electrode. The spark electrode projects a predetermined distance into the combustion chamber so that the axis of the injector nozzle passes through the spark gap. A puff in the form of a short, abrupt blast of the gaseous fuel is expelled across the spark to produce a well-defined turbulent plume of the injected gaseous fuel. The time and duration of the electric spark and the fast-acting valve actuator controls the length of time it takes to open the fast-acting valve and the length of time the fast-acting valve remains open. The electric spark occurs after an appropriate predetermined time after the opening of the fast-acting valve, when the gaseous fuel plume in the vicinity of the spark electrode. Then, the ambient fuel-air mixture and the injected gaseous fuel in the combustion chamber are simultaneously ignited. A clear improvement in both ignition and combustion of lean fuel mixtures is thus provided.